This application is based on and incorporates herein by reference Japanese Patent Application No. 2001-336497 filed on Nov. 1, 2001.
The present invention relates to vehicular occupant restraint system and method.
In the vehicle airbag system, the airbag deployment needs to be started immediately after a collision, and the determination of the seating condition of occupants needs to be made before the start of airbag deployment. The time allowed for the determination is so short that it is difficult to determine the seating condition with accuracy within that time.
Therefore, the seating condition is periodically monitored and determined while the vehicle is traveling. The airbag deployment control is performed based on the latest condition determined immediately before a collision.
If the interval of the periodic determination is long, the condition may not match an actual condition at the collision. Therefore, a proper airbag deployment control may not be performed. Although this problem may be solved by shortening the interval, technical and economic burdens, such as unnecessary battery power consumption for the periodic monitoring and determination, increase.
Furthermore, an electromagnetic wave sensor may be used for the occupant sensor. The electromagnetic wave sensor irradiates an occupant with short wavelength electromagnetic waves such as millimeter waves or microwaves. It determines the seating condition based on how the waves are reflected off the occupant. In this instance, the influence of the electromagnetic wave irradiation on human body needs to be considered.
The present invention therefore has an objective to provide a vehicular occupant restraint system that performs appropriate occupant protecting operations based on the latest and accurate determination of seating condition of the occupant.
The present invention has another objective to provide a vehicular occupant restraint method for determining a current seating condition with accuracy and performing an appropriate occupant protecting operations based on the seating condition.
In the occupant restraint system of the present invention, a probability of occurrence of a potential collision is determined. When the probability is high, seating conditions of vehicle occupants are determined. Then, occupant restraint operations are performed based on the determined seating condition. Therefore, the seating condition determination can be performed in advance of the deployment of an airbag without periodic monitoring, and a current seating condition can be accurately determined. Thus, battery power consumption by the airbag system can be reduced.
Preferably, an occupant sensor emits electromagnetic waves only after the potential collision is predicted in this system. Therefore, the electromagnetic wave irradiation as well as power consumption can be reduced.